


Beast Pill

by PaperFox19



Category: One Piece
Genre: Body Modification, Exhibitionism, Hyperinflation, M/M, Pet Play, Scent Kink, Voyeurism, Yaoi
Language: English
Status: In-Progress
Published: 2019-04-17
Updated: 2019-06-03
Packaged: 2020-01-15 09:38:50
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,946
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18496294
Author URL: https://archiveofourown.org/users/PaperFox19/pseuds/PaperFox19
Summary: Breed wants to do away with humans, so he kidnaps Caeser from the Straw Hats, he gains another asset via Chopper, combining the rumble ball tech with Caeser's research he creates the Beast Pill. It causes what's known as the ancestral animal to awaken inside a human and grant them beast traits. Law didn't know what he was up against he he gets caught up in things, but these things were bound to happen with Luffy involved.





	1. Caught

**Author's Note:**

> Please Read and Review

Beast Pill

Breed wants to do away with humans, so he kidnaps Caeser from the Straw Hats, he gains another asset via Chopper, combining the rumble ball tech with Caeser's research he creates the Beast Pill. It causes what's known as the ancestral animal to awaken inside a human and grant them beast traits. Law didn't know what he was up against he gets caught up in things, but these things were bound to happen with Luffy involved.

Chapter 1 Caught

Trafalgar Law, a boy who ate the Ope Ope no mi, and Monkey D. Luffy who ate the Gum Gum no mi, and became captains of their own respective pirate crews had formed an alliance. Two years after the War of the Best, the Straw Hats had reunited after growing stronger, they saved Fishman Island and picked a fight with Big Mom one of the Four Emperors.

After arriving on Punk Hazard they formed an Alliance to capture a mad scientist named Caeser Clown and destroy the SAD factory. Law had become a warlord for his own purposes, but it gave him access to government restricted areas. They worked together and with the help of Smoker a marine Vice Admiral, they took down two of Joker's aka Doflamingo's best agents Monet and Vergo. This was a heavy blow, not just a loss of his agents but a blow to his business.

Law's plan was to cut off the way for Doflamingo to getting SAD, a substance used for making an artificial devil fruit known as SMILEs. These artificial fruits were big in the New World, some pirates would kill for an army of devil fruit holders. One of the Four Emperors, in fact, Kaidou. Law had a plan of getting Kaidou to kill Doflamingo for him, by pitting the two against each other. This was serious even for Doflamingo.

He had destroyed the machines to make it and kidnapped the only person who knew how to make it. This put Doflamingo in a serious position. He HAD to get Caeser back at all cost or risk Kaidou coming to kill him. So far the plan was going well, not perfect but well…

Luffy was a bit of a wild card, and they had two samurai tagging along. Luffy was his biggest problem at the moment, he's never met anyone so wild and free, he was certainly interesting. Being on his ship, being so close he began to notice things, things that stroked his curiosity. The way he smiled, the things he said, there were times Law would have sworn Luffy's gaze fell on one of his comrades and it was not a normal friendly look.

There was warmth on his ship, not the ship itself; though it was impressive, the crew, Luffy, there was warmth with them, and Law found it difficult from being pulled in. He tried to keep his distance, but Luffy would simply stretch his arms and glomp him. Law didn't get how he could be so carefree, he wasn't used to this kind of stuff. He was trying to focus on the mission.

The crew was on guard, out of fear of Doflamingo's attack, unaware if he'd send someone or come himself. So the crew was a bit on edge despite trying to keep busy. Luffy was bouncing around from one crew member to another it seems.

An attack did come but not from one of Joker's group. It was a man named Breed who was using a gang of animal pirates to do his bidding. Breed had the power of the Peto Peto no mi, it gave him the power to control living things. The animal crew was forced to attack Luffy and his crew, even though they didn't want to.

The Sea Monster Pirates was a gang of sea creatures, led by a familiar Kung-Fu Dugong, they had a black belt penguin, a sumo capybara, an octopus boxer, and a group of sea lapahns. They bumped into Bree and he used his power to make them his pets. Using their strength, they attacked the ship and snatched Caeser and took him away.

Luffy, Law, and Chopper, decided to go after them. The rubber boy left Zoro in charge and whispered something to him before they departed. Law raised a brow at his actions, but again shook his thoughts and stopped starring at Luffy and focused on the mission. They used the Shark Submerge 3 and went after them.

-x-

While Luffy reunited with his former disciple, yes the kung-fu dugong was one Luffy had met before, back in Alabasta. He was so inspired by Luffy's words and teachings, he decided to go out to sea himself and become a pirate.

Breed met with Caeser, the gas man thought he was working for Joker, but no Breed had his own plans for Caeser's skills. He confronted the intruders and Luffy was confused about Breed's powers but he was happy to show them.

He got a green collar on Chopper and forced him to attack Luffy and Law, but to his surprise, he used a rumble ball and went Monster Point! He grew massive and beastly and gave Luffy and Law some trouble.

Law wanted to stop him but Luffy didn't want him to hurt his nakama, and the distraction allowed Breed to strike and the two were collared. He made Chopper stop and ordered Luffy and Law to sit, like dogs. The two were greatly embarrassed, more so by Breed's laugh, he was toying with them. This guy was crazy, he hated humans and claimed animals were better so he wanted to turn humans into beasts and make them better. “Humans are stupid creatures, with silly rules, and foul beliefs, animals follow instincts and they are far more loyal and trusting,” he said.

“You crazy bastard!” Luffy growled, only for Breed to crack his whip.

“You two are my pets now, and you will do as I say.” their collars glowed. “I was just after Caeser, but it seems fortune smiles on me, that mystery ball you used would make an excellent distribution system to humans. Caeser, take Chopper here and get started on the experiment. You two will work with your full ability to make my dream come true.” Their collars glowed and Caeser obeyed.

“Chopper!” Luffy called out, only to get cracked with the whip again.

“Be quiet! Kneel!” he snapped, and Luffy's collar glowed and forced him to obey. “I have big plans for you two, you'll be the first to become part of my new world.”

'He plans to use us as guinea pigs?' Law began to sweat.

“First things first, pets even you incomplete pets have to follow the rules. Pets do not wear clothes!” he said with sinful glee. Law blushed and his eyes went wide. “If you need me to be clear, I order you to strip!”

Their collars glowed and the two began to obey. Their clothing cast aside, from their hats, respective shirts, pants, boxers, shoes, and sandals. Law blushed, his whole face was red, this was humiliating, he was completely naked and exposed, his soft 7-inch dick exposed for all to see.

He knew he shouldn't, but he spared a glance at Luffy and gazed at all his naked glory. He felt his heart flutter at the sight of him. 'He's so big!' Luffy wasn't even hard, his cock was a solid 12 inches soft. Benefits of going through puberty as a rubber man he supposed.

“Don't worry once you become proper pets, and earn your place, I might dress you up,” he said. He ordered their clothes and weapons locked away. He ordered Luffy and Law to their pen, which was basically a sea prism stone cage, and they were each given cuffs with sea prism stone in it.

The duo was locked up for hours. Law kept stealing glances at the very naked Luffy who kept attacking the bars, despite the backlash. He was glad he was so focused, Law was having at not so little problem. His cock was hard and wanting, and even as he tried to calm himself down and will it away, he'd make the mistake of looking at Luffy and he'd get hard all over again. “Straw Hatter, this is bad, we don't have any back upcoming and we don't know if...”

“Three Days!” Luffy said.

“What?”

“We agreed, if we didn't come back by three days, to send a search and rescue party.” Law realized what Luffy was telling Zoro.

“Bit long isn't it?”

“It'll be fine, we still have Chopper, and we have each other, if we can't find a way to escape ourselves, the others will come,” he said.

“Why do you have such confidence, Straw Hatter?” Law looked and it seems Luffy zonked out, he was laid out and snoring. Looks like the sea prism stone finally wore him out. “Guess we just have to survive.”

-x-

The first day seemed to pass on in a blur, they were given food, water, and taken out for “walks”, Law was counting the time till he could cut off Breed's head, with or without his power he wasn't sure yet.

Breed was so happy, he thought it would be days to create it, but with Caeser and Chopper, he was able to make something even better than SMILEs, the Beast Pill! By mixing the SAD formula with Chopper's Rumble Ball formula he was able to create something new.

“Time to test it.” They had made two prototypes, and they had two guinea pigs, that was perfect math. While Chopper could move he couldn't disobey Breed because of the curse.

They stepped before the pen and found Law covering his crotch, and Luffy banging against the bars. “Enough!” Luffy's collar glowed and he was forced to stop. “Now then I have a treat for you two.” He showed the two the beast pills, they were the same size as Chopper's rumble balls only these were green.

“Please stop, don't give it to them,” Chopper begged.

“Oh did Chappy make a bad product?”

“No, it'll work, I'm sure it will, it'll tap into their legacy gene and find the animal in it and cause their bodies to shift, but if you do this there won't be going back, there's no way to dilute it in such a short time, if they even survive at all!” he was tearing up.

“Silly Chappy, that's what I want.” he tossed the pills inside the pen. “Take your medicine!” he commanded. The two tried to resist, Law ignoring his arousal and gripping the collar trying to rip it off, but to no avail, the put the pills in their mouths and crushed the pills with their teeth.

Luffy gasped. His body felt hot, it was like going gear second and gear third at the same time. He choked as he tried to breathe, body shaking and thrashing as his cells, flesh, and bone began to change. His hair grew wild and a touch longer. “Gaaaaahhhhh!”

“Luffy!” Chopper cried.

He looked like he was having a fit, his canines grew larger and more beastly. Black fur spread around his wrists and ankles, his pubes turned into a treasure trail up his abs. His cock grew by an inch soft, and his balls grew larger. Luffy's already plump ass grew plumper and more fur, and shock of shock a monkey tail sprouted up at the base of his spine. The transformation hurt...like hell...like his very soul was boiling.

Law fared no better, his fur matched Luffy's except his looked softer, and his pubes spread fur down and covered his balls making them plump and furry. His cock gained an inch of length, and the base of his penis swelled to form a knot. Law whimpered it hurt worse than he had White Led, he thought he was gonna die, his ears morphed to become fuzzy and canine-like and he sprouted a doggy tail.

“Not bad, not bad very good.” he clapped. “You are full pets now,” the two glared at him. “Now don't be that way I can be a very good master. Law...” the male tensed. “I've been watching this whole time, you've been so pent up, Luffy help Law get off!”

Law looked at Luffy, saw his collar glow and he gulped. Luffy turned to see Law, his hard 8 incher throbbing between his legs. The look Luffy was giving him was making his tail wag. “Traffy...”

To be continued...Sex and Rewards  



	2. Sex and Rewards

**Notes for the Chapter:**

> Please Read and Review

Chapter 2 Sex and Rewards

'Luffy-ya,' Law blushed his tail wagging. His legs spread as Luffy approached, crawling for him, his monkey tail swaying behind him. Luffy took a whiff of Law's crotch, the dog hybrid blushing deeper, his whole face and his ears going red.

“Mmm Traffy!” Luffy descended on his cock, licking the male's hard 8 incher. Each lick had Law's penis pulsing and twitching, he really was pent up. It was hard not to be, he's been stuck in a jail cell naked with Monkey D. Luffy. He's had a bad case of blue balls for a while.

Luffy licked back and forth, going from the base to the tip, then lapping down to lick his heavy balls. “Traffy, are you really like this because of me?” Luffy asked, peeking up at him. Law couldn't say it, so he nodded. “You should have told me, I'd have helped you,” he said before consuming both of his balls and sucking on them.

“Ohhh!” pre-cum started pouring from the tip. His toes flexed and his tail wagged faster. The doctor was becoming a panting mess. Luffy's hands traveled up his legs, caressing the fur and the smoothness of his legs. He moved back up to Law's cock and in one motion he swallowed Law's dick down to the root in one go. “Luffy!”

Luffy hummed as he took a big whiff of Law's musk, his nose nuzzling his thick nest of manly hair. His new animal instincts were intensifying this experience for the rubber man. The taste of his cock and his balls, the rich manly musk, the spice of his arousal, the flavor of his pre-cum, the heat and weight of his dick.

The rubber boy's cock began to stir, his soft 13-inch dick began to swell and grow, reaching 17 inches in length. All it took was a few sucks and Law was bucking into Luffy's mouth cumming hard. Monkey didn't stop sucking him either, his hand coming up to play with his balls.

Not only did he milk a few extra spurts from Law's dick, but his non-stop suction and ball teasing also caused him to cum again! “Luffy-ya stop...ahh fuck...I'm cumming again!” his back arched and he came again, the dog boy was drooling as his seed flooded the monkey boy's mouth. His tail stopped wagging, his body going slack as pleasure overwhelmed the surgeon.

The moment was perfect, he completely forgot he was in a cell or the fact they had an audience. Sadly it all came back as he heard Breed clapping. Luffy was busy cleaning Law's still semi-hard dick, it seems his new transformation had given him a boost of endurance. “Wonderful wonderful, you two put on quite the show. Well Law, did Luffy make you feel good?” When Law didn't answer Breed glared. “Answer me!”

His collar glowed. “Yes!” he moaned.

“Good boy,” he chuckled. “But now it's Luffy who needs to get off, I think he deserves more than a blow job after that performance. Luffy go ahead and mate with Law.”

Law gasped, he saw Luffy's collar glow. He looked down and saw Luffy's long hard cock, he gulped. His hole twitched, and his insides tingled, he didn't know Luffy was a grower. This wasn't how he wanted his first time, but he felt Luffy push his legs up, causing his ass cheeks to spread and expose his tight hole.

Luffy, however, seemed to stop, his body was shaking and he was growling. 'Does he not want to fuck me that badly?' he thinks, his ears flattening. He couldn't help but be negative, not believing Luffy would want him that way, despite the blow job. Luffy's cock was lined up with his hole, the tip rubbing against his pucker.

“Traffy...do you want this?” he asked. He was starting to sweat in his struggle against the control. His eyes widened. “I...I'd rather bite my own dick off than rape someone!”

Law wrapped his arms around Luffy's neck, mildly annoyed the collar was in the way. “Luffy-ya, fuck me, mate me, I want you inside me. Claim me!” Luffy pushed forward and kissed Traffy. He licked his lips and Law parted his lips.

His tongue slipped in and the surgeon kissed back. They made out for a bit, Law growing hard again. Luffy's hands teased Law's perky nipples, devouring the moan he caused. 'Luffy-ya I didn't want to feel this way about you, I plan to take down Doflamingo even if it means my death. So I hardened my heart and tried to ignore the way you make me feel. Now...I just want to feel you, I need you!'

The kiss broke for air, and Luffy kissed down his body. He reached Law's twitching hole and put his kissing skills to other uses. He kissed the dog boy's ass, licking the tight pucker, using his tongue to work his hole open. “Ah ahh Luffy-ya!” his legs slipped over his shoulders.

Luffy kissed his ass deeper, his tongue penetrating his virgin hole. His rubber abilities came into play, stretching as it wiggled deeper and deeper, reaching areas no tongue had ever explored before. “Oh God!” Law's body shuddered.

This rim job took on a whole other level, Luffy's tongue curled and wiggled opening his ass up. Law was in heaven, he felt like he was gonna cum just from Luffy's deep anal kiss. His insides were wet with saliva, and the icing on the cake was his prostate got licked. “Luffy...I'm gonna cum!”

Luffy pulled his tongue back, Law whining at the loss. The rubber man didn't stop at the rimming, he began to stretch Law's tight ass with his fingers. 'He's driving me crazy...just fuck me!' he grit his teeth, growling as his cock felt ready to explode.

He removed his fingers and lined up his cock, his dick was slicked up with pre-cum. “Law, here I come!” Luffy pushed in, the fat head of his dick breaching the boy's ass. Law moaned as his virgin ass was claimed.

Law panted and groaned, trying to relax as he was opened up. Now he was very happy Luffy prepped him so well. His fat cock stretched him wide, and he was taking inch after inch. It felt so good, Luffy was only halfway in before Law was cumming, painting their sweaty bodies in white.

Luffy took this chance, using his orgasm to slide the rest of the way in. Law was so horny he felt no pain even as Luffy's massive rubber dick rearranged his insides. “So big!”

“So tight!” Luffy stilled inside him, just letting Law's body massage his cock.

“Luffy-ya...please move!” he bucked back, grinding his ass into Luffy's pelvis. Luffy smiled and began to move, pulling back till only the tip was inside, only to thrust back in with one smooth motion. The long strong thrusts had Law moaning like a bitch in heat. His stomach bulging from the huge length. “Oh god yes fuck yes!”

Luffy's heavy balls smacked Law's ass with such force it made his cheeks jiggle. His prostate was hit with each pass of Monkey's massive dick. The friction was glorious, the void in Law was getting filled again and again making him smile. If he knew sex with Luffy was this good, he'd have jumped him back at Sabaody.

His strength and stamina seemed to be amplified since his change, and Law was getting the full benefit for it. Luffy also seemed to know the way around a man's body, playing Law like a fiddle to draw out the most pleasure. So it was no surprise that Law came again, his insides tightening around Luffy's thrusting dick.

Luffy growled as his own climax hit, his dick expanding and his balls lurching and a powerful surge of cum flooded Law's insides. Law gasped as his belly expanded from the overflow of cum. He rubbed his swelling belly, feeling a surge of joy.

“Well done, well done, you two can carry on and fall deeper into beasts.” Breed left laughing. It wasn't an exact order, so the two were able to relax a bit. Luffy pulled out, leaving Law's ass gaping and cum slipping out to fill the void.

Law laid across Luffy's lap, face in his crotch, licking and kissing the monkey boy's dick. “I feel so full!” Luffy's cum was leaking out of his ass, but his stomach was still ballooned.

Luffy chuckled. “Yeah, I cum a lot.”

“I don't hate it,” Law panted, his tail wagging. He took in deep whiffs of Luffy's crotch, loving the manly musk. “Can we do it again, once I get feeling in my arms and legs?”

Luffy chuckled again, petting the dog boy. “Yeah, we definitely can.” As soon as Law recovered, he got into the doggy style position, on his hands and knees. Luffy mounted him again, stuffing his already cum filled hole. Law smiled, bucking back against him.

Monkey began to move, this time only pulling back 8 inches and thrusting back in. Doing this kept them connected allowing Luffy to fuck Law faster. He used his tail this time, testing his control over it. The tail reached around and coiled around Law's weeping dick. Luffy's thrusts made the cum in Law's belly slosh inside him.

Law moaned, the fur of Luffy's tail tickling his sensitive dick, plus the tail was able to grip him firmly. “Luffy-ya!”

“Traffy!” his hands came around and toyed with Law's perky nipples, sending the surgeon over the edge and cumming all over the floor. Luffy eventually came, sending Law into a pleasure induce sleep.

Chopper would return later to clean them up. “Luffy...I'm sorry...I...”

Luffy pet his head. “It's okay Chopper, this will all work out.”

Chopper hugged him.

-x-

The next two days were intense, Luffy was learning a lot about Law, and he was learning a lot about himself. Breed made them “perform” for food. Luffy wanted the food yes but he also wanted Law to feel good.

Traffy was learning he was quite the kinky fucker. He got so excited licking Luffy's pits and feet and enjoyed having it done to him in kind. He loved getting stuffed with cum, and there were many naps where he stayed connected with Luffy. What's more, Breed seemed to enjoy them giving tongue baths to each other. He thought he was breaking them, but he was wrong.

With three days passing Luffy knew back up was gonna be on the way. Zoro and Sanji decided to head over, leaving Franky and Brook in charge of the ship. They promised to be back with Luffy.

They snuck onto Breed's ship, but it didn't take long before the two started bickering. Which led to Breed knowing they were there. While they bickered over who would rescue Luffy, Breed got the jump on them and collared them both. “You two must be Straw Hat's crewmates, won't he be surprised. Strip and follow me, it's time for you to take your medicine.”

To be continued


End file.
